1. Field of Invention
This invention relates to electrophotographic printing systems. Specifically, the present invention relates to systems and methods for facilitating fuser replacement in electrophotographic printing systems.
2. Description of the Related Art
Laser printers and copiers are employed in various demanding applications including mass publishing, copying, and home and office printing applications. Such applications often require cost-effective and reliable printers that require minimal maintenance and have user-serviceable and replaceable components.
A conventional electrophotographic printing system often includes a toner cartridge in communication with a developer and an Electrophotographic (EP) drum or transfer belt. A printing application employs a printer driver to send control signals specifying the output to be printed to a printer controller running on the printer. The printer controller selectively aims a laser at the drum via one more controlled mirrors to produce an electrostatic charge pattern on the drum corresponding to the desired printer output. A developer charges the toner in preparation for transfer to the drum. The developer then exposes the drum to the charged, powdery toner, which sticks to the charged areas of the drum. A transfer assembly, which may include a transfer drum or belt and transfer roller, transfers the toner to the output media as a fuser assembly heats and melts the toner. The fuser assembly often includes a fuser roller (fuser) and an adjacent pressure roller. The pressure roller presses the paper against the hot fuser, which is heated by a fuser lamp to fuse the toner to the paper as the paper passes between the fuser roller and pressure roller. A pressure roller actuator may actuate the pressure roller, which then actuates the fuser roller. The printer controller controls the movement of the pressure roller.
The fuser has a surface film that often breaks down and develops toner rings at the edges of the paper path. Toner rings cause print output defects, such as vertical smears on the output media, and may necessitate replacement of the fuser assembly. A paper jam in the fuser assembly may also require removing the fuser. Paper jams are particularly problematic in applications using various plastic-based papers, such as transparencies, which can melt and stick to the fuser.
Unfortunately, replacing and/or servicing the fuser in a conventional laser printer or copier is often time-consuming and expensive. In many conventional electrophotographic printing systems, the fuser is positioned deep within the printer to accommodate printer design and space constraints. Removing the fuser may require removal of other printer parts, various screws, printer housings, panels, and so on. Furthermore, the fuser is often extremely hot, and may burn an unsuspecting user attempting to replace the fuser. Fuser replacement or repair often requires an outside specialist with detailed knowledge of the printer model. In addition, the fuser is often built into an expensive fuser assembly that must be replaced along with the fuser. Consequently, repairing or replacing a faulty fuser is often prohibitively expensive and may cost more than the printer itself.
To overcome various hazards and expenses associated with replacing fusers in electrophotographic printing systems, various user-replaceable fuser assemblies were developed. Unfortunately, these assemblies often require replacement of the entire fuser assembly with the fuser. The fuser assembly may include a pressure roller, a fuser wicking mechanism, a toner heat lamp, and so on, which are often less susceptible to wear than the fuser itself. Furthermore, in conventional printers employing user-replaceable fuser assemblies, the position of the fuser relative to other printer components may necessitate endwise insertion (where the insertion direction is parallel to the longitudinal axis of the fuser) of the cartridge. Endwise insertion places undesirable design constraints on mechanisms for actuating the cartridge door. Consequently, these printers typically require complicated and expensive cartridge door assemblies to facilitate opening the cartridge door when the user inserts the fuser cartridge and closing the door when the user removes the fuser cartridge. An exemplary user-replaceable fuser assembly is disclosed in U.S. Pat. No. 5,200,785, entitled IMAGE-FORMING APPARATUS FUSER AND CUSTOMER REPLACEABLE FUSING ROLLER CARTRIDGE THEREFOR by Linn C. Hoover et al. The fuser cartridge of the above-referenced patent is inserted and removed perpendicular to the paper path. Consequently, fuser paper jams are difficult to clear. For example, if print media becomes stuck in the fuser, the stuck print media may tear when the fuser is removed from the printer, leaving torn print media stuck in the printer. Furthermore, the fuser cartridge of the above-referenced patent lacks grips to facilitate single-handed cartridge removal.
Hence, a need exists in the art for a cost-effective and safe system and method for facilitating fuser replacement in electrophotographic printing systems that does not require endwise insertion or simultaneous replacement of the pressure roller and fuser.
The need in the art is addressed by the user-replaceable fuser cartridge of the present invention. In the illustrative embodiment, the inventive fuser cartridge is adapted for use with an electrophotographic printing system, such as a laser printer. The fuser cartridge includes a first mechanism for partially encasing a fuser. The position of the first mechanism is substantially fixed when installed, yet free to move in a predetermined direction relative to the fuser. A second mechanism facilitates gripping the first mechanism. A third mechanism selectively encases a remaining portion of the fuser not encased by the first mechanism when the fuser cartridge is removed from the electrophotographic system via the second mechanism.
In a more specific embodiment, the first mechanism includes a shield, and the predetermined direction is perpendicular to a longitudinal axis of the fuser. The shield is partially curved and concentric with the fuser. The second mechanism includes a handle mounted on the first mechanism. A fuser cartridge receptacle is built into the electrophotographic printing system and has an open end sufficiently shaped to accommodate lateral insertion of the fuser so that insertion and removal of the fuser cartridge occurs parallel to the paper path. The third mechanism includes an automatically actuated fuser cartridge door that opens and closes upon insertion and removal of the fuser cartridge and accompanying fuser into and out of the fuser cartridge receptacle, respectively, to selectively expose the fuser or to completely encase the fuser, respectively.
The novel design according to an embodiment of the present invention is facilitated by the first and third mechanisms, which represent a cost-effective approach to selectively encasing a fuser upon removal and exposing the fuser upon insertion into a fuser cartridge receptacle. The cost-effective approach is facilitated by the overall design of the first and third mechanisms, which enables lateral insertion of the fuser cartridge into the fuser cartridge receptacle. Mounting a handle to the fixed fuser shield facilitates lateral insertion and removal of the fuser cartridge into an electrophotographic printing system by a user. By employing a handle mounted to a fuser shield also facilitates single-handed operation; helps protect the user from hot surfaces; and facilitates general device handling, such as clearing paper jams by enhancing a user""s grip on the cartridge.